1. Field of the Invention
This invention relates to a delivery device of piled corrugated fiberboard boxes which holds corrugated fiberboard boxes in a hopper in a piled mode and sends out successively the lowermost one among the piled corrugated fiberboard boxes one by one.
2. Description of the Prior Art
One conventional delivery device of piled corrugated fiberboard boxes is configured as shown in FIG. 6 and operates in such a manner that corrugated fiberboard boxes 1 are continuously supplied to, piled and held in a hopper 3 by upper and lower belts 9 and 10 and the lowermost one 1a among the thus piled corrugated fiberboard boxes 1 held in the hopper 3 is successively sent out one by one by a send-out conveyor belt 8. Front and rear wall portions of the hopper 3 are formed by a squaring plate 4 disposed on the supply side of the lower belt 10 and rocked via an arm by an eccentric cam 5, a rear sheet stop 11 disposed below the squaring plate, a front portion 7 of a backstop assembly 6, etc.; the backstop assembly 6 is designed so that its longitudinal position is adjustable so as to harmonize with the size of the corrugated fiberboard box 1 by means of a shifting unit (not shown) including screw shafts and the like; and the front portion 7 is attached to the backstop assembly 6 so that a gap left at the lower end thereof is adjustable.
The corrugated fiberboard box 1 is formed by being subjected in successive steps to the processes of recessing, ruled-line drawing, gluing, and folding. Thus, after folding, box 1 (as shown in FIG. 7) has a laminated glued portion 2 formed through folding and gluing, thereby leaving upper and lower sheets 12 and 13 on either side of the box. However, there is a possibility that some discrepancy appears at the laminated glued portion 2 as shown in FIG. 8, or a deformed corrugated fiberboard box results having edges 12a and 13a warped at marginal portions as shown in FIG. 9. Under ordinary circumstances, deformation of such corrugated fiberboard boxes as above is alleviated in the inside of the hopper 3 while receiving the action of the squaring plate 4 and the weight of the piled corrugated fiberboard boxes, the lowermost corrugated fiberboard box 1a is sent out through the gap below the front patch 7 one by one by means of a friction force existing between it and the send-out conveyor belt 8, the send-in rate of the upper and lower belts 9 and 10 is made to balance with the send-out rate or amount achieved by the send-out conveyor belt 8, and hence, the number of corrugated fiberboard boxes held in the hopper 3 is regulated to a given amount.
The lowermost corrugated fiberboard box 1a is sent out owing to the difference between one friction force existing between it and the send-out conveyor belt 8 and caused by a pushing pressure produced by the weight of the piled corrugated fiberboard boxes and another friction force existing between it and the lowermost-but-one corrugated fiberboard box. However, if the second-mentioned friction force existing between the first and the second lowermost boxes increases, the first-mentioned friction force due to the weight of the boxes increases and some discrepancy tends to appear at the laminated glued portion 2 of the lowermost corrugated fiberboard box 1a as shown in FIG. 8. In view of the aforementioned phenomenon, the rear sheet stop 11 is provided to hold high the second and higher-ranked corrugated fiberboard boxes so as to reduce the load, caused by the total weight of the piled corrugated fiberboard boxes lying on the lowermost one, which is applied to the lowermost corrugated fiberboard box 1a being sent out; that is, this rear sheet stop 11 functions so as to halve the weight of a pile acting on the lowermost corrugated fiberboard box 1a.
According to the conventional delivery device described above, the corrugated fiberboard box 1 whose paste at the laminated glued portion 2 is semi-dried is supplied to, dropped and piled in the hopper 1, thus, such a deformed corrugated fiberboard box as shown in FIG. 8 may be reformed within the hopper 3 into such a desired shape as shown in FIG. 7 so as to fall within a certain precision of folding. However, since the paste of the lowermost corrugated fiberboard box 1a to be sent out also is not dried perfectly, in spite of the load due to the weight of the pile being halved by the rear sheet stop 11, some discrepancy arises again at the laminated glued portion 2 to deform the box as shown in FIG. 8 because the box is sent out by means of the friction force existing between it and the send-out conveyor belt 8, and such an inconvenience as above tends to occur often in the winter season during which the rate of drying of paste is low.